Using external hardware effects on the mixbus'

I have a Yamaha SPX2000 that I want to use as a send/return device within mixbus but are having an issue getting the effects to come back into the channel. I have a RME 96/52 with 3X ADAT, SPDIF and AES I can manage to see level movement on the SPX when I increase the send amount but I hear no effect on the channel. VST work ok as an insert or send and yes I do activate the send and return after changing the routing. Thanks.

@jcaldwe1: did you try just using a (port) insert ?

thank you for the responses I ended up using the inserts and all is ok now…

Or you could try to use the external device w/o ardour first, sending a signal directly from jack and listening to the returned signal. Maybe you can narrow down the failing point